Ultra Thin Wall Mat Design and Optimization with Hybrid Mats

The advance in emission control technologies towards Ultra Thin Wall (UTW) substrates has presented packaging challenges. With respect to mounting mats, there are two main problems with the traditional intumescent mats. First, intumescent mats typically generate too much pressure during assembly over their normal mounting range for the promised substrate strength; this can lead to broken substrates during assembly. Second, large pressure spikes occur in heated intumescent mats that could cause broken substrates in the field. As a result, non-intumescent mats are being used to alleviate the two main problems that occur with intumescent mats. A third alternative, a composite or “hybrid” mat, may offer a higher level of performance at lower cost compared to the non-intumescent mat solutions. The hybrid mats referred to in this paper consist of a layer of intumescent mat and a layer of non-intumescent mat. Some advantages that a hybrid mat offers are a broader mounting range and increased high temperature resiliency compared to the non-intumescent mats normally recommended for UTW applications. In addition, a well-designed hybrid mat does not have the high temperature pressure peaks that traditional intumescent mats do under high temperature operation.